Update Volume Dialog selectors to match the new ones.

We've changed some of the ids and logic for the volume redesign. This
change updates the tests, so they pass when the flag is on.

Flag: com.android.systemui.volume_redesign
Bug: 369993959
Test: atest vendor/google_testing/integration/tests/scenarios/src/android/platform/test/scenario/sysui/volume
Change-Id: I9f9c547bedc1a0df4c5f6678c100a8c5f81ed697